Broadly speaking, there are two of signage application for LEDs; those in which the LEDs are viewed directly, and those in which the LEDs act as a backlight.

Examples of the former include highway variable message signs (VMS), scoreboards, moving message panels, arrival and departure boards in airports and railway stations and other single-color information signs, as well as full-color displays seen in sports venues or on advertising hoardings.

LEDs are also used to illuminate exit and emergency signs, as backlights for channel letters that are seen as replacements for neon, and as backlights in liquid-crystal display (LCD) panels.

The displays segment was worth 18% of the total HB-LED market in 2003, or about $485 million, according to Strategies Unlimited. Full-color displays accounted for slightly over $300 million. Sports stadiums continue to be a major area for growth, while other strong sectors include concerts, rentals, retail and advertising.

In the next few years, the Beijing Olympics is expected to create huge demand for LED displays, while new, lower cost display technologies are also likely to drive growth.

LEDs are already widely used as backlights for LCDs in mobile appliances such as phones handsets, PDAs and digital cameras. A number of companies have already deployed LED backlights in larger LCD displays, including LCD TVs.